A damping linear actuator for damping the roll of a vehicle is disclosed in JP2005-106242A.
The linear actuator disclosed in JP2005-106242A includes an outer tube, an inner tube slidably inserted into the outer tube and a rod standing from a bottom portion of the outer tube and sliding contact with the inner periphery of the inner tube. The inner tube is supported by a bearing mounted on the inner periphery of an opening of the outer tube and a bearing mounted on the outer periphery of the rod.
The linear actuator includes a plurality of annular permanent magnets held side by side in an axial direction on the outer periphery of the inner tube and a plurality of coils held on the inner periphery of the outer tube and facing the permanent magnets. The direction and magnitude of a current flowing in each coil are controlled to generate a thrust force for relatively displacing the outer tube and the inner tube in the axial direction, thereby damping the roll of a vehicle.